scholarly journals The formation processes and development characteristics of sandbars due to outburst flood triggered by landslide dam overtopping failure

2020 ◽  
Author(s):  
Xiangang Jiang ◽  
Haiguang Cheng ◽  
Lei Gao ◽  
Weiming Liu
Keyword(s):  
Failure Process ◽  
Landslide Dam ◽  
Dam Failure ◽  
Average Height ◽  
Formation Processes ◽  
Outburst Flood ◽  
Channel Changes ◽  
River Bed ◽  
Essential Form ◽  
Overtopping Failure

Abstract. Sandbars are an essential form of riverbed morphology which could be affected by landslide dams. However, few studies have focused on the formation processes and development characteristics of sandbars triggered by outburst flood. In such a way, eight group dam failure experiments with 4 to 7 times of dam length movable bed is carried out to study the temporal and spatial distributions of 25 sandbars along the riverbeds, the sandbars geometric characteristics, and the influence of outburst flow hydraulic characteristics on developments of sandbars. The results show that sandbars are formed after peak discharge of outburst flow. The number of sandbars is 0.4 to 1.0 times the ratio of river bed length to dam length. Besides, sandbars have the characteristic of lengthening towards upstream during the failure process. Sandbars' upstream edges have a more extensive development than sandbars downstream edges. The length of a sandbar along the channel changes faster than the sandbar's width and height. The sandbars' length and width are about 10 to 80 and 1 to 7 times of average height, respectively, and the average heights of sandbars are about 1 to 3.5 times the maximum particle size. Sandbars' lengths make a more significant impact on sandbars' volumes than widths and heights. It found that the Froude number has a significant influence on the sediment carrying capacity. And the sediment concentrations in volumes of the outburst flow at the upstream edges of all sandbars are greater than those at the downstream edges of sandbars. Meanwhile, the sediment carrying capacities of the outburst flow at the upstream edges of sandbars are smaller than those at the sandbars' downstream edges. And the differences between the sediment concentrations and the sediment carrying capacities determine the sedimentation or entrainment. The results can reference the research on the river channel's geomorphological characteristics affected by the outburst flood.

scholarly journals The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure

2021 ◽  
Vol 9 (5) ◽  
pp. 1263-1277
Author(s):  
Xiangang Jiang ◽  
Haiguang Cheng ◽  
Lei Gao ◽  
Weiming Liu
Keyword(s):  
Field Data ◽  
Failure Process ◽  
Landslide Dam ◽  
Dam Failure ◽  
Dimensionless Length ◽  
Channel Changes ◽  
Outburst Floods ◽  
Characteristics Analysis ◽  
Movable Bed ◽  
The Relationship

Abstract. Boulder bars are a common form of riverbed morphology that could be affected by landslide dams. However, few studies have focused on the formation and geometry characteristics of boulder bars due to outburst floods triggered by landslide dam failure. In such a way, eight group landslide dam failure experiments with a movable bed length of 4 to 7 times the dam length with 25 boulder bars were carried out. In addition, 38 boulder bars formed in the field triggered by four landslide dam failures were investigated. The aim of this paper is to study the formation and geometry characteristics of boulder bars along the riverbeds. The results show that boulder bars are formed after peak discharge of outburst flow. The number of boulder bars is 0.4 to 1.0 times the ratio of riverbed length to dam bottom length. Besides, boulder bars have the characteristic of lengthening upstream during the failure process. A boulder bar's upstream edge has a more extensive development than a boulder bar's downstream edge. The length of a boulder bar along the channel changes faster than the boulder bar's width and height. After the dam failure, the boulder bar's length is about 8 to 14 times its width. The relationship between the ratio of boulder bar length to width and the boulder bar's dimensionless length could be described with a hyperbolic equation. The dimensionless area of the boulder bar increases linearly with the dimensionless area of the river section, and the linear ratio is about 0.5. With the field data, this demonstrates that the formation and geometry characteristics of boulder bars in tests are consistent with the field boulder bars. Therefore, the results in this paper are credible and can be applied to the riverbed's geomorphological characteristics analysis triggered by overtopped landslide dam failure. The plentiful experimental and field data could contribute to the community boulder bar research.

scholarly journals A Preliminary Study of the Failure Modes and Process of Landslide Dams Due to Upstream Flow

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1115 ◽  
Author(s):  
Xinghua Zhu ◽  
Jianbing Peng ◽  
Cheng Jiang ◽  
Weilong Guo
Keyword(s):  
Large Scale ◽  
Failure Modes ◽  
Mine Waste ◽  
Failure Process ◽  
Landslide Dam ◽  
Experimental Tests ◽  
Field Investigation ◽  
Dam Failure ◽  
Experimental Conditions ◽  
Landslide Dams

In the process of mineral development, large-scale flash floods (or debris flows) can be induced by the failure of landslide dams formed by the disorganized stacking of mine waste. In this study, the modes and processes of mine waste dam failures were explored using 13 experimental tests based on the field investigation of landslide dams in the Xiaoqinling gold mining area in China. Our 13 mine waste dam experiments exhibited three failure modes: (i) Piping, overtopping, and erosion; (ii) overtopping and soil collapse; and (iii) overtopping and erosion. In addition, the failure processes of the landslide dams included impoundment, seepage, overtopping, and soil erosion. Different experimental conditions would inevitably lead to different failure processes and modes, with the failure modes being primarily determined by the seepage characteristics. Overtopping was the triggering condition for dam failure. The landslide dam failure process was determined based on the particle size of the mine waste and the shape of the dam. These findings will provide a scientific reference for the prevention and mitigation of natural hazards in mining areas.

scholarly journals Assessment methodology for the prediction of landslide dam hazard

2014 ◽  
Vol 14 (3) ◽  
pp. 557-567 ◽  
Author(s):  
S. F. Dal Sasso ◽  
A. Sole ◽  
S. Pascale ◽  
F. Sdao ◽  
A. Bateman Pinzòn ◽  
...  
Keyword(s):  
Landslide Dam ◽  
Dam Failure ◽  
River Networks ◽  
Assessment Methodology ◽  
European Research ◽  
Research Project ◽  
Morphological Alterations ◽  
River Bed ◽  
Basin Scale ◽  
Deterministic And Probabilistic Approaches

Abstract. This paper represents a contribution to the study of hazard caused by the interaction between landslides and river courses. The effects of such interferences are often catastrophic and could include the formation of upstream lakes, potential dam failure, river bed dynamics and morphological alterations. These scenarios could be substantially reduced if it was possible to predict the eventuality that a moving landslide would block the river. This is a complex topic because it involves composite geomorphic phenomena concerning both hillslope and river systems and their interpretation, through model approaches, is still under development and testing. In this study, a methodology developed in the framework of European Research Project IMPRINTS (FP7) was adopted and integrated in order to identify the areas of triggering and propagation of landslides and to characterize the possible scenarios of the interaction with river networks. Different deterministic and probabilistic approaches, calibrated using a case test in the middle valley of the Noce River in Basilicata (Italy), were applied and compared at basin scale.

scholarly journals Experimental Investigation of the Outburst Discharge of Landslide Dam Overtopping Failure

2021 ◽  
Vol 9 ◽  
Author(s):  
Mingjun Zhou ◽  
Zhenming Shi ◽  
Gordon G. D. Zhou ◽  
Kahlil Fredrick E. Cui ◽  
Ming Peng
Keyword(s):  
Landslide Dam ◽  
Longitudinal Direction ◽  
Peak Discharge ◽  
Outburst Flood ◽  
Outburst Floods ◽  
Flume Tests ◽  
Loose Deposits ◽  
Overtopping Failure ◽  
Solids Content ◽  
Inflow Discharge

Research on the factors and mechanisms that influence outburst floods are essential for estimating outflow hydrographs and the resulting inundation. In this study, large flume tests are conducted to investigate the effects of the upstream inflow and the presence of loose erodible deposits on the breaching flow and the subsequent outburst floods. Experimental results reveal that hydrographs of the breaching flow and outburst flood can be divided into three stages where each stage is separated by inflection points and peak discharges. It is found that the larger the inflow discharge, the larger the peak discharge of the outburst flood and the shorter the time needed to reach the peak and inflection discharges of the outburst flood. The breaching flow decreases along the longitudinal direction at rates that increase with the inflow discharge. The ratio between the length of the upstream dam shoulder and the dam width is inversely related to the ratio of the outburst discharge to inflow discharge. We also show that the presence of loose deposits at the dam toe can amplify the peak discharge of outburst flood by increasing the solids content of the water flow.

scholarly journals Modeling Flood Peak Discharge Caused by Overtopping Failure of a Landslide Dam

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 921
Author(s):  
Hechun Ruan ◽  
Huayong Chen ◽  
Tao Wang ◽  
Jiangang Chen ◽  
Huibin Li
Keyword(s):  
Landslide Dam ◽  
Calculation Model ◽  
Peak Discharge ◽  
Mitigation Measures ◽  
Dam Failure ◽  
Jinsha River ◽  
Simulation Accuracy ◽  
Flood Peak ◽  
Overtopping Failure ◽  
Dam Overtopping

Overtopping failure often occurs in landslide dams, resulting in the formation of strong destructive floods. As an important hydraulic parameter to describe floods, the peak discharge often determines the downstream disaster degree. Based on 67 groups of landslide dam overtopping failure cases all over the world, this paper constructs the calculation model for peak discharge of landslide dam failure. The model considers the influence of dam erodibility, breach shape, dam shape and reservoir capacity on the peak discharge. Finally, the model is compared with the existing models. The results show that the new model has a higher accuracy than the existing models and the simulation accuracy of the two outburst peak discharges of Baige dammed lake in Jinsha River (10 October 2018 and 3 November 2018) is higher (the relative error is 0.73% and 6.68%, respectively), because the model in this study considers more parameters (the breach shape, the landslide dam erodibility) than the existing models. The research results can provide an important reference for formulating accurate and effective disaster prevention and mitigation measures for such disasters.

scholarly journals Large-Scale Field Test Study on Failure Mechanism of Non-Cohesive Landslide Dam by Overtopping

2021 ◽  
Vol 9 ◽  
Author(s):  
Liang Li ◽  
Xingguo Yang ◽  
Jiawen Zhou ◽  
Jieyuan Zhang ◽  
Gang Fan
Keyword(s):  
Large Scale ◽  
Discharge Channel ◽  
Failure Process ◽  
Field Tests ◽  
Landslide Dam ◽  
Development Stage ◽  
Dam Failure ◽  
Process Time ◽  
Scale Field ◽  
Large Scale Field

In recent years, landslide lake disasters occur frequently in southwest mountainous areas of China. Considering the influence of dam size and discharge channel location, three large-scale field tests were carried out in a natural river to study the failure process and mechanism of non-cohesive soil landslide dam, and the process and mechanism of non-cohesive landslide dam breach were analyzed. The results show that the dam size and discharge channel location have a significant influence on the breach mechanism of the landslide dam. The dam failure process can be divided into three stages: the initiation stage, the development stage and the failure stage. When the discharge channel is located close to the bank, the width of the breach is smaller, and the volume of the residual dam body is larger. The more stable the dam body is, the longer the breach process time is, and the smaller the peak discharge is. This study can provide a scientific reference for the emergency disposal and risk assessment of landslide dam.

scholarly journals Assessment methodology for the prediction of landslide dam hazard

2013 ◽  
Vol 1 (5) ◽  
pp. 5663-5694 ◽  
Author(s):  
S. F. Dal Sasso ◽  
A. Sole ◽  
S. Pascale ◽  
F. Sdao ◽  
A. Bateman Pinzòn ◽  
...  
Keyword(s):  
Landslide Dam ◽  
Dam Failure ◽  
River Networks ◽  
Morphological Alterations ◽  
Side Slope ◽  
Basilicata Region ◽  
River Bed ◽  
Basin Scale ◽  
The Right ◽  
Deterministic And Probabilistic Approaches

Abstract. This paper represents a contribution to the study of hazard caused by the interaction between landslides and river courses. The effects of such interferences are often catastrophic and could include the formation of backwater lakes, potential dam failure, river bed dynamics and morphological alterations. These scenarios could be substantially reduced if it was possible to predict the eventuality that a moving landslide could block the river. This is a complex topic because it involves composite geomorphic phenomena concerning both hillslope and river systems and their interpretation, through model approaches, is still under development and testing. In this study, a methodology developed in the framework of the European Research Project IMPRINTS (FP7), was adopted and integrated in order to identify the areas of triggering and propagation of landslides and to characterize the possible scenarios of the interaction with river networks. Different deterministic and probabilistic approaches, calibrated using a case test in the middle valley of Noce River in Basilicata region (Italy), were applied and compared at basin scale. In this area, a landslide mobilized in July 2007 on the right side slope of the river invaded a gravel-bed reach, characterized by a narrow and confined section, causing its progressive morpho-hydrodynamic change.

Extreme mass wasting during 2021 Dhauli Ganga event in the Higher Himalaya: insight from the landscape

2021 ◽  
Author(s):  
Anand Kumar Pandey ◽  
Kotluri Sravan Kumar ◽  
Virendra Mani Tiwari ◽  
Puranchand Rao ◽  
Kirsten Cook ◽  
...  
Keyword(s):  
Debris Flow ◽  
Extreme Event ◽  
Rock Avalanche ◽  
Slope Instability ◽  
Mass Wasting ◽  
Outburst Flood ◽  
Flood Warning ◽  
River Bed ◽  
High Flood ◽  
Glacial Lake Outburst Flood

<p>The slope instability and associated mass wasting are among the most efficient surface gradation processes in the bedrock terrain that produce dramatic landscape change and associated hazards. The wedge failure in periglacial Higher Himalaya terrain on 7th February in Chamoli, Uttarakhand (India) produced >1.5 km high rock avalanche, which amalgamated with the glacial debris on the frozen river bed produced massive debris flow along the high gradient Rishi Ganga catchment. The high-velocity debris flow and a surge of high flood led to extensive loss of life and infrastructures and issuing the extreme event flood warning along the Alakananda-Ganga river, despite there was no immediate extreme climatic event. The affected region is the locus of extreme mass wasting events associated with Glacial Lake Outburst Flood (GLOF) and Landslide Lake Outburst Flood (LLOF) in the recent past. We analyzed the landscape to understand its control on the 7th February 2021 Rishi Ganga event and briefly discuss other significant events in the adjoining region e.g. 1893/1970 Gohna Tal/Lake LLOF and 2013-Uttarakhand events in Chamoli, which have significance in understanding the surface processes in Higher Himalayan terrain.</p>

AN INTEGRATED APPROACH TO PREDICT OUTFLOW HYDROGRAPH DUE TO LANDSLIDE DAM FAILURE BY OVERTOPPING AND SLIDING

2008 ◽  
Vol 52 ◽  
pp. 151-156 ◽  
Author(s):  
Ripendra AWAL ◽  
Hajime NAKAGAWA ◽  
Kenji KAWAIKE ◽  
Yasuyuki BABA ◽  
Hao ZHANG
Keyword(s):  
Landslide Dam ◽  
Integrated Approach ◽  
Dam Failure ◽  
Outflow Hydrograph
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